Another common issue is getting the rear shocks set properly. All the way soft may be way too soft and you're bottoming out. Proper adjustment is to get the sag to be 1/3 of total travel with you sitting on it ready to ride. Have some helpers (Edit: lift the rear to top out the suspension.), hold it upright and level, Maybe a level taped to the tank, across speedo if there or gas fill or? You measure from a point above the rear axle to the floor. Then you sit on it or a helper who weighs the same and re-measure. Most cruisers seem to be around 3" of travel in the rear, so approx. 1" lower. I thought my 412's were no good until I got them set right. For me on the 750 Ace, that was the 3rd(middle) notch, 4th for two-up.